1. Field of the Invention
Liquid crystal panels, which are flat display screens for displaying information, are widely used in fields such as the personal computer field. Backlight type display units are widely used in laptop personal computers, cellular phones and the like, for which reduction in thickness of the device is especially strongly needed. In backlight type display units, a liquid crystal panel is irradiated from the back side with light.
2. Description of the Related Art
A light source extending in the form of a line is arranged on the side surface of a liquid crystal panel in a backlight type display unit. In addition, a backlight type display unit has a light guide plate bonded to the back surface of the liquid crystal panel. In such a backlight type display unit, light generated from the light source is guided by the light guide plate to the liquid crystal panel. The light is then further diffused by the light guide plate to be radiated from the back side of the liquid crystal panel. According to such a backlight type display unit, the light source and the like are arranged beside the liquid crystal panel, where space is relatively abundant. Therefore, the display unit is flat.
A display unit using a liquid crystal panel generally accommodates the liquid crystal panel. A backlight, a drive board and the like are attached to the display unit, which is placed in a housing for purposes such as good appearance. The entire housing is preferably composed of a strong metal or the like in order to reduce the thickness and weight of the device, and also to protect the breakable liquid crystal panel from impact such as falling.
Recently, laptop personal computers have been equipped with a wireless communication function. Such a personal computer often has an antenna for wireless communication installed beside the liquid crystal panel. Therefore, if the entire housing of the personal computer were made of metal, which is an electrically conductive material, the antenna would be unable to transmit and receive electric waves. For this reason, a housing is used which has a first member composed of a strong metal. A second member composed of plastic or the like which permits electric waves to pass is fixed around the first member. Such a housing contains the liquid crystal panel in the first member portion and contains the antenna or the like in the second member portion.
An example of a method for fixing the first member to the second member is to superpose and screw together the outer edge of the first member and the inner edge of the second member. However, according to this method, light of the backlight may leak from the gap between the first member and the second member. This impairs the feeling of luxury or the impression of high quality with the personal computer.
Japanese Patent Laid-Open No. 11-311952 is known as a reference for alleviating leakage of light of the backlight. This reference discloses a housing in which a rear surface member made of metal is fixed to a front surface member made of plastic.
The rear surface member covers the rear surface of the liquid crystal panel, while the front surface member surrounds the front surface side of the liquid crystal panel. The rear surface member has a surface contacting the front surface member in the form of a slope. The front surface member has an outer edge which is bent. The front surface member is screwed to the slope of the rear surface member through the bent portion. Adherence of the superposed portion of the front surface member to the rear surface member is improved in this way, and leakage of light of the backlight in the housing can be alleviated.
This reference does not configure the rear surface side housing case in the form of one plate by a plurality of members of different materials. In this reference, the rear surface member, which is made of metal, is fixed to the front surface member, which is made of plastic, at the side surface of the liquid crystal panel. Therefore, the rear surface of the liquid crystal panel is covered by the metal rear surface member, so that an antenna for wireless communication cannot be disposed in the upper housing.
This problem occurs not only in personal computers and cellular phones but generally in display units accommodating a backlight type display panel in the housing.